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1.
ISME J ; 17(3): 326-339, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36517527

RESUMEN

Horizontal gene transfer is a powerful source of innovations in prokaryotes that can affect almost any cellular system, including microbial organelles. The formation of magnetosomes, one of the most sophisticated microbial mineral-containing organelles synthesized by magnetotactic bacteria for magnetic navigation in the environment, was also shown to be a horizontally transferrable trait. However, the mechanisms determining the fate of such genes in new hosts are not well understood, since non-adaptive gene acquisitions are typically rapidly lost and become unavailable for observation. This likely explains why gene clusters encoding magnetosome biosynthesis have never been observed in non-magnetotactic bacteria. Here, we report the first discovery of a horizontally inherited dormant gene clusters encoding biosynthesis of magnetosomes in a non-magnetotactic phototrophic bacterium Rhodovastum atsumiense. We show that these clusters were inactivated through transcriptional silencing and antisense RNA regulation, but retain functionality, as several genes were able to complement the orthologous deletions in a remotely related magnetotactic bacterium. The laboratory transfer of foreign magnetosome genes to R. atsumiense was found to endow the strain with magnetosome biosynthesis, but strong negative selection led to rapid loss of this trait upon subcultivation, highlighting the trait instability in this organism. Our results provide insight into the horizontal dissemination of gene clusters encoding complex prokaryotic organelles and illuminate the potential mechanisms of their genomic preservation in a dormant state.


Asunto(s)
Magnetosomas , Magnetospirillum , Magnetospirillum/genética , Magnetosomas/genética , Bacterias/genética , Bacterias Gramnegativas/genética , Bacterias Aerobias/genética , Familia de Multigenes , Fenómenos Magnéticos , Proteínas Bacterianas/genética
2.
J Carcinog Mutagen ; 7(1)2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27158556

RESUMEN

BACKGROUND: RNA polymerase (pol) III transcribes a variety of untranslated RNAs responsible for regulating cellular growth and is deregulated in a variety of cancers. In this study, we examined gender differences in RNA pol III transcription in vitro and in vivo. METHODS: Expression levels of U6 snRNA, tMet, and known modulators of RNA pol III transcription were assayed in male and female derived adenocarcinoma (AC) lung cancer cell lines and male and female C57BL/6J mice using real time quantitative PCR. Methylation status of the U6 snRNA promoter was determined for lung and liver tissue isolated from male and female C57BL/6J mice by digesting genomic DNA with methylation sensitive restriction enzymes and digestion profiles were analyzed by qPCR using primers spanning the U6 promoter. RESULTS: Here, we demonstrate that RNA pol III transcription is differentially regulated by EGCG in male and female derived AC lung cancer cell lines. Basal RNA pol III transcript levels are significantly different in male and female derived AC lung cancer cell lines. These data prompted an investigation of gender specific differences in RNA pol III transcription in vivo in lung and liver tissue. Herein, we report that U6 snRNA RNA pol III transcription is significantly stimulated in the liver tissue of male C57BL/6J mice. Further, the increase in U6 transcription correlates with a significant inhibition in the expression of p53, a negative regulator of RNA pol III transcription, and demethylation of the U6 promoter in the liver tissue of male C57BL/6J mice. CONCLUSIONS: To the best of our knowledge, this is the first study demonstrating gender specific differences in RNA pol III transcription both in vivo and in vitro and further highlights the need to include both male and female cell lines and animals in experimental design.

3.
Klin Monbl Augenheilkd ; 224(3): 207-9, 2007 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-17385124

RESUMEN

The oculo-cerebro-renal syndrome of Lowe (OCRL) is a rare X-chromosomal disorder characterised by the triad of congenital cataracts, renal tubular dysfunction, and mental retardation. Typically complete opacification and discoid deformation of the lenses are seen, indicating a developmental defect in early embryogenesis. We report on a 35-year-old patient with a mild Lowe syndrome phenotype including incomplete lenticular opacities. Clinical findings suggest that the gene product of the mutated allele (IVS19 + 1G > A) identified in the patient exhibits some residual function.


Asunto(s)
Catarata/diagnóstico , Catarata/genética , Síndrome Oculocerebrorrenal/diagnóstico , Síndrome Oculocerebrorrenal/genética , Monoéster Fosfórico Hidrolasas/genética , Sitios de Empalme de ARN/genética , Adulto , Predisposición Genética a la Enfermedad/genética , Humanos , Masculino , Mutación
4.
J Nephrol ; 18(4): 374-81, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16245240

RESUMEN

BACKGROUND: The regulation of renal hemodynamics is closely related to the L-arginine (L-Arg)/nitric oxide (NO) pathway. NO - metabolized from L-Arg - is capable of improving renal function in ischemic and toxic acute renal failure (ARF), while NO synthase (NOS) inhibition induces deterioration in renal function. The mortality rate in patients with septic shock is increased when treated with a non-selective NOS inhibitor, while the incidence of ARF requiring renal replacement therapy is unaffected. To date, there are no studies on the impact of NOS substrate (L-Arg) and inhibitor (L-NMMA) on renal function in early lipopolysaccharide (LPS)-induced ARF. METHODS: ARF was induced by intravenous (i.v.) LPS. Animals were treated with L-Arg, L-NMMA (NOS substrate and inhibitor), a combination of both or saline. Glomerular filtration rate (GFR), urine flow, fractional sodium excretion, excretion of NO metabolism stable end products and blood pressure (BP) were recorded at baseline, after ARF induction, during drug infusion and thereafter. RESULTS: L-Arg induced better GFR during infusion. Excretion of the NO metabolism end products was highest in the L-Arg group and lowest in the NOS inhibitor group. L-Arg administration had no influence on BP, while L-NMMA induced a slight elevation. CONCLUSIONS: We conclude that exogenous L-Arg exerts beneficial effects in early LPS-induced ARF in rats during drug infusion, while NOS inhibition has no influence on GFR. Subcellular compartmentalization of the L-Arg pool in cytoplasma and the rapid utilization of exogenous L-Arg in such a micro-environment could explain this effect, which has been observed in other ARF models and was called the "L-Arg paradox". In further studies the effects of early and prolonged administration of L-Arg in endotoxinemia should be investigated.


Asunto(s)
Lesión Renal Aguda/fisiopatología , Inhibidores Enzimáticos/farmacología , Tasa de Filtración Glomerular/fisiología , Óxido Nítrico Sintasa/antagonistas & inhibidores , omega-N-Metilarginina/farmacología , Lesión Renal Aguda/tratamiento farmacológico , Lesión Renal Aguda/orina , Animales , Presión Sanguínea/efectos de los fármacos , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Escherichia coli , Femenino , Tasa de Filtración Glomerular/efectos de los fármacos , Lipopolisacáridos/toxicidad , Óxido Nítrico/orina , Ratas , Ratas Sprague-Dawley , Sodio/orina , Urodinámica/efectos de los fármacos
5.
Brain Res ; 918(1-2): 101-6, 2001 Nov 09.
Artículo en Inglés | MEDLINE | ID: mdl-11684047

RESUMEN

The purpose of the present study was to determine whether spinal interneurons play a role in the regulation of sympathetic activity in spinally intact rats. In acutely spinally transected rats, we have described a population of spinal interneurons that, by virtue of correlations between their ongoing firing rates and the magnitude of ongoing renal sympathetic nerve activity (RSNA), are candidates for generators of sympathetic activity. Further evidence for a sympathetic role for these neurons comes from our observation that cervical spinal stimulation that reduces RSNA also reduces their discharge rates. In chloralose-anesthetized, spinally intact and spinally transected rats, we recorded ongoing RSNA and the ongoing activities of T(10) dorsal horn and intermediate zone interneurons, and we determined the incidence of sympathetically related neurons in these rats by cross-correlating their activities with RSNA. The incidence of correlated neurons was much smaller in spinally intact than in spinally transected rats. We stimulated the dorsolateral, C(2-3) spinal cord before and after acute C(1) spinal transection. Dorsolateral cervical stimulation in spinally transected rats reduced both RSNA and the activities of most T(10) interneurons, but stimulation in spinally intact rats increased RSNA while still reducing the activities of most T(10) interneurons. Both the low incidence of sympathetically correlated spinal neurons in intact rats and the dissociation between the effects of cervical stimulation on RSNA and the discharge rates of spinal interneurons argue against these neurons playing a major role in regulating sympathetic activity in intact rats.


Asunto(s)
Potenciales de Acción/fisiología , Interneuronas/fisiología , Riñón/inervación , Red Nerviosa/fisiología , Circulación Renal/fisiología , Médula Espinal/fisiología , Fibras Simpáticas Posganglionares/fisiología , Animales , Tronco Encefálico/fisiología , Vértebras Cervicales , Vías Eferentes/fisiología , Estimulación Eléctrica , Interneuronas/citología , Masculino , Ratas , Ratas Wistar , Médula Espinal/citología , Traumatismos de la Médula Espinal/fisiopatología , Fibras Simpáticas Posganglionares/citología
6.
Exp Clin Immunogenet ; 18(4): 199-205, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11872950

RESUMEN

The class II transactivator is a major transcriptional factor acting on the promoters of MHC class II genes. Transcription of the CIITA gene is driven by four alternative promoters, which exhibit cell-type-specific activity. The CIITA promoter III (PIII) is constitutively active in B cells, whereas promoter IV (PIV) becomes activated upon interferon-gamma activation. The aim of this study was to investigate whether these two promoters exhibit a sequence variability like the MHC class II promoters do. We isolated PIII and PIV fragments from healthy individuals and rheumatoid arthritis patients and screened them for sequence polymorphisms. Single base pair substitutions within the CIITA PIV were found in 9% of the individuals analyzed. The majority of the substitutions were located upstream of the known cis-acting elements of the promoter. PIII was non-polymorphic. To evaluate the functional relevance of the detected polymorphism we cloned variable PIV upstream of the luciferase reporter gene. Such prepared constructs were transfected into monocytes, melanoma and HeLa cells, which were subsequently stimulated with interferon-gamma. The analysis of promoter activities did not reveal significant differences in all three cell types. We conclude that the level of CIITA expression does not vary within the population. Thus the differences in the level of MHC class II expression, which are observed between individuals, stem for the polymorphisms of the MHC class II promoters themselves.


Asunto(s)
Genes MHC Clase II , Polimorfismo Genético , Regiones Promotoras Genéticas , Transactivadores/genética , Animales , Artritis Reumatoide/genética , Artritis Reumatoide/inmunología , Secuencia de Bases , Línea Celular , ADN/genética , Células HeLa , Humanos , Ratones , Datos de Secuencia Molecular , Polimorfismo Conformacional Retorcido-Simple , Homología de Secuencia de Ácido Nucleico
7.
Transpl Int ; 13 Suppl 1: S282-5, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11112013

RESUMEN

Kidneys obtained from brain dead donors show inferior graft survival compared to living donation. The effects of brain death itself are thought to be partly responsible for these results. We, therefore, examined levels of catecholamines, the vasoconstricting hormones AT II, ET-1 and renin activity, pituitary hormones, and their correlation to pro-inflammatory cytokines and cytokine receptors. In 17 brain dead patients and 19 preoperative neurosurgical patients, these parameters were measured by HPLC, RIA and ELISA. Brain death resulted in massive increases in serum catecholamines, AT II and ET-1, as well as PRA, whereas thyroid and adrenal hormone levels remained unchanged. We found a significant correlation with rises in IL-6 and soluble TNF and IL-2 receptors as markers for the activation of immunological cascades. We concluded that these effects could be directly and indirectly responsible for the impaired organ perfusion and function observed in brain death.


Asunto(s)
Muerte Encefálica , Citocinas/sangre , Hormonas/sangre , Receptores de Citocinas/sangre , Donantes de Tejidos , Adulto , Angiotensina II/análisis , Antígenos CD/sangre , Endotelina-1/sangre , Epinefrina/sangre , Femenino , Humanos , Interleucinas/sangre , Masculino , Persona de Mediana Edad , Norepinefrina/sangre , Hormonas Hipofisarias/sangre , Receptores de Interleucina-2/sangre , Receptores del Factor de Necrosis Tumoral/sangre , Receptores Tipo II del Factor de Necrosis Tumoral , Renina/sangre
8.
Genes Dev ; 14(20): 2650-63, 2000 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-11040218

RESUMEN

Transcription initiation at RNA polymerase III promoters requires transcription factor IIIB (TFIIIB), an activity that binds to RNA polymerase III promoters, generally through protein-protein contacts with DNA binding factors, and directly recruits RNA polymerase III. Saccharomyces cerevisiae TFIIIB is a complex of three subunits, TBP, the TFIIB-related factor BRF, and the more loosely associated polypeptide beta("). Although human homologs for two of the TFIIIB subunits, the TATA box-binding protein TBP and the TFIIB-related factor BRF, have been characterized, a human homolog of yeast B(") has not been described. Moreover, human BRF, unlike yeast BRF, is not universally required for RNA polymerase III transcription. In particular, it is not involved in transcription from the small nuclear RNA (snRNA)-type, TATA-containing, RNA polymerase III promoters. Here, we characterize two novel activities, a human homolog of yeast B("), which is required for transcription of both TATA-less and snRNA-type RNA polymerase III promoters, and a factor equally related to human BRF and TFIIB, designated BRFU, which is specifically required for transcription of snRNA-type RNA polymerase III promoters. Together, these results contribute to the definition of the basal RNA polymerase III transcription machinery and show that two types of TFIIIB activities, with specificities for different classes of RNA polymerase III promoters, have evolved in human cells.


Asunto(s)
ARN Polimerasa III/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Transcripción Genética , Secuencia de Aminoácidos , Clonación Molecular , Humanos , Datos de Secuencia Molecular , Regiones Promotoras Genéticas , ARN Polimerasa III/metabolismo , ARN Viral/genética , Ribonucleoproteína Nuclear Pequeña U4-U6/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae , Homología de Secuencia de Aminoácido , TATA Box , Factores Asociados con la Proteína de Unión a TATA , Factor de Transcripción TFIIIB
9.
J Neurophysiol ; 83(5): 2699-707, 2000 May.
Artículo en Inglés | MEDLINE | ID: mdl-10805670

RESUMEN

We have shown previously that in the acutely spinalized anesthetized rat the activities of many dorsal horn interneurons (DHN) at the T(10) level are correlated positively with both ongoing and stimulus-evoked renal sympathetic nerve activity (RSNA) and therefore may belong to networks generating RSNA after acute, cervical, spinal transection. In the present study, we recorded from both DHN and interneurons in the intermediate zone (IZN) of the T(10) spinal segment in acutely C(1)-transected, chloralose-anesthetized, artificially respired rats. The activities of a similar percentage of IZN and DHN were correlated positively with ongoing RSNA, but the peaks of spike-triggered averages of RSNA based on the activity of IZN were larger, relative to dummy averages, than spike-triggered averages of RSNA based on the activity of DHN. Sympathetically correlated DHN and IZN differed in their responses to noxious somatic stimuli. Most correlated DHN had relatively simple somatic fields; they were excited by noxious stimulation of the T(10) and nearby dermatomes and inhibited by stimulation of more distal dermatomes. As we have shown previously, the excitatory and inhibitory fields of these neurons were very similar to fields that, respectively, excited and inhibited RSNA. On the other hand, the somatic fields of 50% of sympathetically correlated IZN were significantly more complex, indicating a difference between either the inputs or the processing properties of IZN and DHN. Sympathetically correlated IZN and DHN also differed in their responses to colorectal distension (CRD), a noxious visceral stimulus. CRD increased RSNA in 11/15 rats and increased the activity of most sympathetically correlated T(10) IZN. On the other hand, CRD decreased the activity of a majority of sympathetically correlated T(10) DHN. These observations suggest that the same stimulus may differentially affect separate, putative, sympathoexcitatory pathways, exciting one and inhibiting the other. Thus the magnitude and even the polarity of responses to a given stimulus may be determined by the modality and location of the stimulus, the degree to which multiple pathways are affected by the stimulus, and the ongoing activity of presympathetic neurons, at multiple rostrocaudal levels, before stimulation. A multipathway system may explain the variability in autonomic responses to visceral and somatic stimuli exhibited in spinally injured patients.


Asunto(s)
Fibras Adrenérgicas/fisiología , Hemodinámica/fisiología , Interneuronas/fisiología , Células del Asta Posterior/fisiología , Médula Espinal/fisiología , Potenciales de Acción/fisiología , Animales , Presión Sanguínea/fisiología , Colon/inervación , Colon/fisiología , Potenciales Evocados/fisiología , Frecuencia Cardíaca/fisiología , Interneuronas/citología , Masculino , Inhibición Neural/fisiología , Estimulación Física , Células del Asta Posterior/citología , Ratas , Ratas Sprague-Dawley , Recto/inervación , Recto/fisiología , Médula Espinal/citología , Médula Espinal/cirugía , Traumatismos de la Médula Espinal/fisiopatología
10.
Transpl Int ; 13(6): 436-42, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11140242

RESUMEN

Nephrotoxicity is one of the main side effects of calcineurin-inhibitors. The influence of tacrolimus on the renal vasculature has not been well described. We have therefore examined the effects of tacrolimus on renal functional parameters as well as the contribution of the NO-system in a model of ischemic acute renal failure (ARF). Induction of ARF was achieved by clamping both renal arteries of female Sprague-Dawley rats. During the experiment, RBF, GFR, MAP, RVR and FENa were determined during infusion of vehicle, TAC, TAC and the NOS-activator L-arginine, and TAC and NOS-inhibition due to L-NMMA. TAC induced a significant rise in RVR with further decrease of RBF and GFR. Simultaneous L-arginine-infusion could reverse these effects during the infusion without complete restoration to preischemic levels. NOS-inhibition increased MAP and RBF without any effect on GFR. FENa did not differ significantly between the groups. Tacrolimus in the situation of ischemic acute renal failure causes vasoconstriction of pre- and postglomerular vessels with a further deterioration of renal function. L-arginine abolishes the functional deterioration, most likely due to increased NO-liberation.


Asunto(s)
Lesión Renal Aguda/prevención & control , Arginina/uso terapéutico , Inhibidores de la Calcineurina , Inmunosupresores/toxicidad , Isquemia/fisiopatología , Riñón/irrigación sanguínea , Donantes de Óxido Nítrico/uso terapéutico , Circulación Renal/efectos de los fármacos , Tacrolimus/toxicidad , Vasoconstricción/efectos de los fármacos , Lesión Renal Aguda/inducido químicamente , Animales , Arginina/administración & dosificación , Arginina/farmacología , Presión Sanguínea/efectos de los fármacos , Constricción , Diuresis/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Femenino , Tasa de Filtración Glomerular/efectos de los fármacos , Inmunosupresores/farmacología , Isquemia/etiología , Glomérulos Renales/irrigación sanguínea , Glomérulos Renales/efectos de los fármacos , Óxido Nítrico/biosíntesis , Donantes de Óxido Nítrico/administración & dosificación , Donantes de Óxido Nítrico/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Ratas , Ratas Sprague-Dawley , Arteria Renal , Tacrolimus/farmacología , Resistencia Vascular/efectos de los fármacos , omega-N-Metilarginina/farmacología
12.
J Clin Invest ; 102(7): 1279-85, 1998 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-9769319

RESUMEN

Nitric oxide (NO) synthesized within mammalian sinoatrial cells has been shown to participate in cholinergic control of heart rate (HR). However, it is not known whether NO synthesized within neurons plays a role in HR regulation. HR dynamics were measured in 24 wild-type (WT) mice and 24 mice in which the gene for neuronal NO synthase (nNOS) was absent (nNOS-/- mice). Mean HR and HR variability were compared in subsets of these animals at baseline, after parasympathetic blockade with atropine (0.5 mg/kg i.p.), after beta-adrenergic blockade with propranolol (1 mg/kg i.p.), and after combined autonomic blockade. Other animals underwent pressor challenge with phenylephrine (3 mg/kg i.p.) after beta-adrenergic blockade to test for a baroreflex-mediated cardioinhibitory response. The latter experiments were then repeated after inactivation of inhibitory G proteins with pertussis toxin (PTX) (30 microgram/kg i.p.). At baseline, nNOS-/- mice had higher mean HR (711+/-8 vs. 650+/-8 bpm, P = 0.0004) and lower HR variance (424+/-70 vs. 1,112+/-174 bpm2, P = 0.001) compared with WT mice. In nNOS-/- mice, atropine administration led to a much smaller change in mean HR (-2+/-9 vs. 49+/-5 bpm, P = 0.0008) and in HR variance (64+/-24 vs. -903+/-295 bpm2, P = 0.02) than in WT mice. In contrast, propranolol administration and combined autonomic blockade led to similar changes in mean HR between the two groups. After beta-adrenergic blockade, phenylephrine injection elicited a fall in mean HR and rise in HR variance in WT mice that was partially attenuated after treatment with PTX. The response to pressor challenge in nNOS-/- mice before PTX administration was similar to that in WT mice. However, PTX-treated nNOS-/- mice had a dramatically attenuated response to phenylephrine. These findings suggest that the absence of nNOS activity leads to reduced baseline parasympathetic tone, but does not prevent baroreflex-mediated cardioinhibition unless inhibitory G proteins are also inactivated. Thus, neuronally derived NO and cardiac inhibitory G protein activity serve as parallel pathways to mediate autonomic slowing of heart rate in the mouse.


Asunto(s)
Presión Sanguínea/fisiología , Subunidades alfa de la Proteína de Unión al GTP Gi-Go/metabolismo , Frecuencia Cardíaca/fisiología , Óxido Nítrico Sintasa/metabolismo , Animales , Atropina/farmacología , Sistema Nervioso Autónomo/efectos de los fármacos , Sistema Nervioso Autónomo/fisiología , Barorreflejo/efectos de los fármacos , Barorreflejo/fisiología , Presión Sanguínea/efectos de los fármacos , Electrocardiografía/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Homeostasis , Ratones , Ratones Noqueados , Modelos Cardiovasculares , Óxido Nítrico Sintasa/deficiencia , Óxido Nítrico Sintasa/genética , Óxido Nítrico Sintasa de Tipo II , Fenilefrina/farmacología , Propranolol/farmacología , Transducción de Señal/fisiología
13.
Immunogenetics ; 48(4): 266-72, 1998 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9716646

RESUMEN

In all vertebrates the major histocompatibility complex (MHC) class II genes are polymorphic in their coding regions as well as in their promoter control elements. This polymorphism correlates with a variability in peptide binding and a variability in transcriptional activities. There is, however, one exception to this rule, which is the mouse H2-Ea gene or the corresponding human DRA gene. So far and for unkown reasons no polymorphism has been observed in these loci. We sequenced the distal transcriptional control elements of the H2-Ea, H2-Eb, and H2-Ab genes from the mouse haplotypes H2d, H2k, H2q, and H2z, and in contrast to the promoter and coding regions a sequence polymorphism can be detected which is limited to the H2-Ea gene. In transfection experiments this polymorphism can be seen to influence haplotype-specifically the transcriptional activities in B cells. This finding strongly suggests an evolutionary pressure towards a haplotype-specific expression pattern in all four MHC class II genes. The genetic differences in control elements of MHC class II genes may well contribute to differential immune reactivities and to immune disorders like allergies or autoimmune diseases.


Asunto(s)
Elementos de Facilitación Genéticos , Regulación de la Expresión Génica , Genes MHC Clase II/genética , Polimorfismo Genético , Secuencia de Aminoácidos , Animales , Ratones , Datos de Secuencia Molecular , Células Tumorales Cultivadas
14.
Crit Rev Oral Biol Med ; 9(1): 23-37, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-9488246

RESUMEN

The p53 tumor suppressor protein plays a central role in maintaining genomic integrity. It does so by occupying a nodal point in the DNA damage control pathway. When cells are subject to ionizing radiation or other mutagenic events, p53 mediates cell cycle arrest or programmed cell death (apoptosis). Furthermore, some evidence suggests that p53 plays a role in the recognition and repair of damaged DNA. Biochemically, p53 is a sequence-specific transcriptional stimulator and a non-specific transcriptional repressor but also engages in multiple protein-protein interactions. Conversely, disruption of the p53 response pathway strongly correlates with tumorigenesis. p53 is functionally inactivated by structural mutations, neutralization by viral products, and non-mutational cellular mechanisms in the majority of human cancers. p53-deficient mice have a highly penetrant tumor phenotype, with over 90% tumor incidence within nine months. In some cancers, direct physical evidence exists identifying the p53 gene as a target of known environmental carcinogens such as UV light and benzolalpyrene in cancers of the skin and lung. When p53 loss occurs, cells do not get repaired or eliminated but rather proceed to replicate damaged DNA, which results in more random mutations, gene amplifications, chromosomal re-arrangements, and aneuploidy. In some experimental models, loss of p53 confers resistance to anticancer therapy due to loss of apoptotic competence. The translational potential of these discoveries is beginning to be tested in novel p53-based therapies.


Asunto(s)
Regulación Neoplásica de la Expresión Génica , Genes p53 , Neoplasias/etiología , Proteína p53 Supresora de Tumor/fisiología , Animales , Apoptosis , Diferenciación Celular , Transformación Celular Neoplásica/genética , Daño del ADN , Reparación del ADN , Terapia Genética , Humanos , Ratones , Ratones Noqueados , Ratones Transgénicos , Mutación , Proteína p53 Supresora de Tumor/antagonistas & inhibidores , Proteína p53 Supresora de Tumor/química
15.
Neurology ; 50(2): 475-9, 1998 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9484375

RESUMEN

The sera of patients with Lambert-Eaton myasthenic syndrome (LEMS) contain autoantibodies against several extracellular and intracellular components of the voltage-gated calcium channel (VGCC)/synaptic vesicle release complex. An example of the latter are anti-beta-subunit antibodies (anti-MysB antibodies). We constructed a full-length cDNA clone of a human VGCC beta-subunit to produce purified beta-subunit fusion protein (MysB protein). Using this protein, we demonstrated that anti-beta-subunit antibodies are present in the sera of 23% of LEMS patients and only, in low titer, in 2% of small cell lung cancer patients without LEMS. The presence of anti-beta-subunit antibodies was closely associated with high titers of P/Q- and N-type VGCC antibodies. Immunization of rats with the purified MysB protein induced high antibody titers, but no signs of neurologic dysfunction were found. We conclude that anti-beta-subunit antibodies are not likely to interfere with ion channel function, but their presence could explain the cross-reactivity of LEMS sera with several subtypes of VGCCs and the lack of correlation between anti-VGCC antibody titer and clinical severity of disease.


Asunto(s)
Autoanticuerpos/sangre , Canales de Calcio/inmunología , Síndrome Miasténico de Lambert-Eaton/inmunología , Proteínas del Tejido Nervioso/inmunología , Animales , Donantes de Sangre , Canales de Calcio/análisis , Canales de Calcio/metabolismo , Canales de Calcio Tipo L , Membrana Celular/metabolismo , Cerebelo/metabolismo , Corteza Cerebral/metabolismo , Clonación Molecular , Electrofisiología , Femenino , Humanos , Síndrome Miasténico de Lambert-Eaton/diagnóstico , Síndrome Miasténico de Lambert-Eaton/fisiopatología , Sustancias Macromoleculares , Ratas , Ratas Endogámicas Lew , Proteínas Recombinantes de Fusión/inmunología , Valores de Referencia
16.
Nat Med ; 4(1): 84-7, 1998 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9427611

RESUMEN

Nitric oxide (NO) is well established as a neurotransmitter in the central and peripheral nervous systems. More recently, another gas, carbon monoxide (CO) has also been implicated in neurotransmission. In the nervous system CO is formed by a subtype of heme oxygenase (HO) designated HO2. HO2 is localized to discrete neuronal populations in the brain resembling localizations of soluble guanylyl cyclase, which is activated by CO. CO may also function in the peripheral autonomic nervous system, in conjunction with NO. The majority of ganglia in the myenteric plexus possess both HO2 and neuronal NO synthase (NOS). Defects in myenteric plexus neurotransmission occur both in mice with targeted deletion of genes for HO2 and neuronal NOS. HO2 also occurs in other autonomic ganglia including the petrosal, superior cervical and nodose ganglia. Neuronal NOS is localized to neurons regulating male reproductive behavior, such as penile erection, and NOS inhibitors prevent erection. Because of the other parallels between NO and CO, we speculated that CO may play a role in male reproductive behavior. In the present study we describe HO2 localization in neuronal structures regulating copulatory reflexes. Reflex activity of the bulbospongiosus muscle, which mediates ejaculation and ejaculatory behavior, is markedly diminished in mice with targeted deletion of the gene for HO2 (HO2-).


Asunto(s)
Eyaculación/fisiología , Hemo Oxigenasa (Desciclizante)/deficiencia , Hemo Oxigenasa (Desciclizante)/fisiología , Conducta Sexual Animal , Animales , Copulación , Eyaculación/genética , Electromiografía , Endotelio Vascular/enzimología , Ganglios Autónomos/enzimología , Ganglios Autónomos/fisiología , Isoenzimas/deficiencia , Isoenzimas/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos , Ratones Noqueados , Actividad Motora , Plexo Mientérico/enzimología , Plexo Mientérico/fisiología , Neuronas/enzimología , Óxido Nítrico Sintasa/análisis , Erección Peniana , Pene/irrigación sanguínea , Pene/inervación , Pene/fisiología , Tiempo de Reacción , Uretra/enzimología
17.
J Neurooncol ; 34(2): 139-44, 1997 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9210060

RESUMEN

Leptomeningeal carcinomatosis is a painful and debilitating complication of cancer. Indwelling reservoirs provide continuous assess to the subarachnoid space, making leptomeningeal cancer potentially amenable to gene therapy. Adeno-associated virus (AAV) is a defective virus not associated with any human disease. We used an AAV vector to transduce medulloblastoma (DAOY) cells in a nude rat model of leptomeningeal disease. After intraventricular injection of vector carrying the bacterial lacZ gene, beta-galactosidase positive cells were found in the implanted tumor and in ependymal and subependymal cells but not in underlying normal brain parenchyma. No evidence of virally-mediated toxicity was noted in the animals. The results of this pilot study demonstrate that AAV vectors may be used to transfer and express foreign genes in established leptomeningeal tumors.


Asunto(s)
Neoplasias Cerebelosas/terapia , Técnicas de Transferencia de Gen , Terapia Genética/métodos , Meduloblastoma/terapia , Neoplasias Meníngeas/terapia , Espacio Subaracnoideo , Proteínas E1A de Adenovirus/biosíntesis , Animales , Antígenos Virales de Tumores/biosíntesis , Línea Celular , Neoplasias Cerebelosas/patología , Dependovirus , Vectores Genéticos , Humanos , Inyecciones Intraventriculares , Riñón , Meduloblastoma/patología , Neoplasias Meníngeas/patología , Ratas , Proteínas Recombinantes/análisis , Proteínas Recombinantes/biosíntesis , Trasplante Heterólogo , Células Tumorales Cultivadas , beta-Galactosidasa/análisis , beta-Galactosidasa/biosíntesis
18.
J Neurophysiol ; 77(6): 2966-74, 1997 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9212249

RESUMEN

In mammals with an intact neuraxis, most sympathetic nerve activity is generated by brain stem systems. Therefore these systems have attracted much more attention than spinal systems that generate excitatory inputs to sympathetic preganglionic neurons. The purpose of this study was to determine whether, within hours of C1 spinal cord transection, spinal dorsal horn neurons (DHNs) play a role in generating sympathetic nerve activity. Experiments were conducted in chloralose-anesthetized rats. We recorded renal sympathetic nerve activity (RSNA) in the left renal nerve, and we recorded the activity of neurons located in the left dorsal horn at T2, T8, T10, T13, and L2. We also recorded the activity of neurons in the right dorsal horn at T10. The somatic fields and cutaneous modalities of most neurons were determined. Spike-triggered averaging was used to determine relationships between the ongoing activity of DHNs and ongoing RSNA. In the left dorsal horn, bursts of ongoing activity of 16% of DHNs at T8 and 43% of DHNs at T10 were positively correlated with bursts of ongoing RSNA at latencies of 59 +/- 8 (SE) ms. At no other level on the left side, nor in the T10 segment on the right side, was the activity of DHNs correlated with RSNA. DHNs with activity correlated with RSNA were located only in dorsal horn laminae III-V. Deeper laminae were not investigated in these experiments. The activity of all sympathetically correlated DHNs exhibited bursts of action potentials with interspike intervals of < 10 ms. All but one of the sympathetically correlated DHNs exhibited wide-dynamic-range modalities. The modalities of sympathetically uncorrelated neurons were more heterogeneous. Brief (5-10 s) noxious cutaneous stimulation of mid- and lower thoracic dermatomes on the left side excited all sympathetically correlated DHNs and simultaneously increased RSNA. The excitatory cutaneous fields of sympathetically correlated neurons were circumscribed by the excitatory fields for RSNA. The excitatory cutaneous fields of some sympathetically uncorrelated DHNs extended beyond the excitatory fields for RSNA. Noxious cutaneous stimulation of the extremities on the left side that decreased RSNA simultaneously decreased the activity of all sympathetically correlated DHNs. These data provide electrophysiological evidence that, in spinally transected rats, a population of DHNs may generate or convey excitatory input to renal sympathetic preganglionic neurons.


Asunto(s)
Tronco Encefálico/fisiología , Ganglios Espinales/fisiología , Plasticidad Neuronal/fisiología , Médula Espinal/fisiología , Sistema Nervioso Simpático/fisiología , Potenciales de Acción/fisiología , Animales , Fibras Autónomas Preganglionares/fisiología , Desnervación , Lateralidad Funcional/fisiología , Riñón/inervación , Masculino , Vías Nerviosas/fisiología , Neuronas/fisiología , Ratas , Ratas Sprague-Dawley , Tiempo de Reacción/fisiología
19.
Cell Tissue Res ; 288(2): 293-306, 1997 May.
Artículo en Inglés | MEDLINE | ID: mdl-9082965

RESUMEN

We studied the location, distribution, and density of uterine nerve bundles in virgin, full-term pregnant, and early postpartum female rats. In the virgin, a low-magnification analysis of uterine whole-mounts stained for acetylcholinesterase revealed fibers both in close association with blood vessels and coursing freely within muscle or connective tissue in the mesometrium and the uterine body. Higher magnification analysis of sections treated immunohistochemically with antibodies to the ubiquitous neuronal protein gene product 9.5, tyrosine hydroxylase, and calcitonin gene-related peptide indicated that the greatest density of nerve bundles was in the mesometrial triangle and intramyometrial region. Although the majority of bundles were associated with blood vessels, many coursed freely, particularly in the myometrial and endometrial layers. The density of innervation within the body of the uterus was heterogeneous. For instance, both innervated and noninnervated spiral arteries branched from the same innervated circumferential artery. In the term pregnant rat, we observed a profound denervation within all layers of the body of the uterus. The few remaining nerve bundles tended to be associated with blood vessels, and they were confined to the intramyometrial region. Within 48 h postpartum, both the number and density of nerve bundles increased. Long tortuous bundles, not seen in the full-term rat, were observed. The present study is the first to describe and illustrate the pattern of uterine innervation in virgin, full-term pregnant, and early postpartum rats over a wide range of magnifications.


Asunto(s)
Acetilcolinesterasa/análisis , Degeneración Nerviosa/fisiología , Neuronas/fisiología , Preñez/fisiología , Útero/inervación , Vías Aferentes/química , Vías Aferentes/fisiología , Animales , Péptido Relacionado con Gen de Calcitonina/análisis , Femenino , Secciones por Congelación , Inmunohistoquímica , Fibras Nerviosas/química , Fibras Nerviosas/fisiología , Periodo Posparto , Embarazo , Ratas , Ratas Sprague-Dawley , Tirosina 3-Monooxigenasa/análisis
20.
J Natl Cancer Inst ; 89(5): 381-5, 1997 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-9060960

RESUMEN

BACKGROUND: Some patients with cancer develop antibodies against the p53 tumor suppressor protein. The presence of these antibodies in serum has been associated with the expression of mutant p53 by the tumor and in some studies with a poorer survival. PURPOSE: The goals of this study were to determine the prevalence of anti-p53 antibodies in the serum of patients with newly diagnosed small-cell lung cancer (SCLC) and to assess the clinical relevance of the presence of these antibodies in the serum, particularly their relationship with tumor response to treatment and with patient survival. METHODS: In this prospective study, serum was obtained from 170 patients at the time of diagnosis of SCLC who were to subsequently receive platinum- or doxorubicin-based chemotherapy at any one of four hospitals in Barcelona, Spain, from October 1991 through June 1994. Normal human sera from blood bank donors (n = 50) served as controls. The presence of anti-p53 antibodies was determined by western blot analysis with the use of purified recombinant p53 protein. As of January 1996, 96.5% of the patients had been treated and observed in the study, for a median follow-up time of 33.5 months. Survival was estimated by the Kaplan-Meier method. Cox proportional hazards regression and unconditional logistic regression analyses were conducted. All P values resulted from two-sided tests. RESULTS: Anti-p53 antibodies were detected in the serum of 27 (16%) of the 170 patients studied. None of 50 serum samples from normal individuals contained anti-p53 antibodies. Analysis of pretreatment clinical characteristics demonstrated that a weight loss of less than 5% (P = .025), a serum lactic acid dehydrogenase (LDH) level of less than 450 U/L (P = .002), and limited stage disease (i.e., tumor confined to one hemithorax, with local and regional lymph node positivity for tumor cells and/or ipsilateral pleural effusion allowed) (P < .001) were associated with a statistically significant complete response to therapy. The presence of serum anti-p53 antibodies was not associated with clinical characteristics, such as age (P = .622), functional status (P = 1.0), disease stage (P = .634), complete response to treatment (P = .572), and survival (P = .492) or with any laboratory parameters including known prognostic factors in SCLC, such as serum sodium or LDH concentration (P values of .731 and .246, respectively). CONCLUSIONS AND IMPLICATIONS: The presence of anti-p53 antibodies in the serum of patients with newly diagnosed SCLC was not associated with any clinical characteristics or prognostic markers, suggesting that, in this context, the measurement of anti-p53 antibodies is not a useful prognostic marker.


Asunto(s)
Anticuerpos Antineoplásicos/sangre , Carcinoma de Células Pequeñas/inmunología , Neoplasias Pulmonares/inmunología , Proteína p53 Supresora de Tumor/inmunología , Anciano , Western Blotting , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Pronóstico , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Análisis de Supervivencia
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